1. Field of the Invention
The present invention relates to a heat sink assembly, and more particularly to a heat sink assembly having a heat sink and a fastener assembly which can conveniently and reliably attach the heat sink to an electronic device.
2. Description of Related Art
A heat sink is usually placed in thermal contact with an electronic package such as a central processing unit (CPU), and transfers heat through conduction away from the electronic package so as to prevent over-heating of the electronic package. Usually, a heat sink is secured to an electronic package by using clips. Nevertheless, the clips are difficult to assemble, and the force exerted by the clips to the heat sink is difficult to control.
On the other hand, a printed circuit board with an electronic component mounted thereon has four holes defined around the electronic component, and a heat sink has four through holes defined in four corners thereof corresponding to the four holes of the printed circuit board. Screws extend through the through holes of the heat sink and the holes of the printed circuit board, and engage in the holes of a back plate attached to a bottom face of the printed circuit board, thereby attaching the heat sink to the electronic component. However, the heat sink is rigidly connected to the electronic component. It is difficult to ensure that the heat sink applies a uniform pressure on the electronic component, thus tending to reduce the efficiency of heat dissipation. Furthermore, the printed circuit board is prone to be deformed due to a rigid connection with the heat sink. Finally, to add the back plate in order to fasten the heat sink to the printed circuit board is costly.
What is needed, therefore, is an improved heat sink assembly which can overcome the above problems.